1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device that comprises pixels having novel structures.
2. Description of the Prior Art
Many liquid crystal displays, such as Multi-domain vertical alignment type liquid crystal display, bear a high contrast ratio, fast response time, and a wide viewing angle by applying an electric field to reorient liquid crystal molecules in the displays.
FIG. 1 is a cross sectional view of a vertical alignment type liquid crystal display according to prior art. In order to alter alignment of liquid crystals 12, a pixel electrode 4 is formed on a lower substrate 2 and a plurality of protrusions 6 are formed at the pixel electrode 4. In addition, a common electrode 10 is formed below an upper substrate 14 and a plurality of protrusions 8 are formed below the common electrode 10. The structure mentioned above results in the liquid crystals 12 tilting a little bit due to the presence of the protrusions 6,8. When voltages are applied to the pixel electrode 4 and the common electrode 10, a transverse-electric field is generated as the dotted-line arrows to reorient liquid crystal molecules 12 in different angles and thus increase the transmittance.
FIG. 2 shows a cross sectional view of another vertical alignment type liquid crystal display according to prior art. The structure of which is similar to the structure shown in FIG. 1, the difference is that a plurality of openings 16 formed by an etching process to replace the protrusions 6. Also, when voltages are applied to the pixel electrode 4 and the common electrode 10, a transverse-electric field is generated as the dotted-line arrows to reorient liquid crystal molecules 12 in different angles and thus increase the transmittance.
In addition, the liquid crystal display comprises a plurality of scan lines and data lines constructing driving circuits, where the data lines are connected to the data drivers, and the scan lines are connected to the scan drivers. Because the resolution of the liquid crystal display is increased, the number of the scan lines and data lines will be inevitably increased, and the cost is also increased. For lowering the cost, the number of the data lines must be decreased.
FIG. 3 shows the structure of the pixels of a conventional liquid crystal display. For simplicity and convenience, only the lower substrate, the substrate for producing transistors thereon, a partial plan view of which is shown. As shown in FIG. 3, in each row of pixel electrode P0-P4, two pixel electrodes across the data line are driven by the same data line, and driven by two different scan lines individually. For example, data line S2 drives both of pixel electrode P1 and pixel electrode P2, scan line G1 drives pixel electrode P1 but scan line G2 drives pixel electrode P2; data line S3 drives both of pixel electrode P3 and pixel electrode P4, scan line G1 drives pixel electrode P3 but scan line G2 drives pixel electrode P4. The structure shown in FIG. 3 can decrease the number of data lines.
A Taiwan Patent, issued number 548615, entitled “Display device having three adjacent pixel electrodes driven by the same data line,” disclose a display device having three adjacent pixel electrodes are selectively driven by the same data line via a first switch, a second switch, and a third switch. The number of data lines can be further decreased.
In each row of pixel electrodes, every two or three pixel electrodes are driven by the same data line as mentioned above has been applied in liquid crystal display devices such as the vertical alignment type as mentioned above. However, some difficulties are encountered. The major difficulty is the arrangement between two adjacent pixel electrodes. The arrangement must consider the fringe field and crosstalk between pixel electrodes. For generating larger pretilt angles, the fringe field should be large enough; for smaller crosstalk, the distance between two pixel electrodes should be increased. However, increasing the distance between two pixel electrodes will lower the aperture ratio. Besides, the fringe field is not large enough and the crosstalk is still troublesome.
Therefore, it would be advantageous to provide a novel liquid crystal display device having novel structure of pixels, especially for every two or three pixel electrodes driven by the same data line, to overcome the defects of the prior art.